diff --git a/cmd/promtool/main.go b/cmd/promtool/main.go
index 5c2029042..2d2c98fbb 100644
--- a/cmd/promtool/main.go
+++ b/cmd/promtool/main.go
@@ -70,9 +70,11 @@ func main() {
 
 	queryCmd := app.Command("query", "Run query against a Prometheus server.")
 	queryCmdFmt := queryCmd.Flag("format", "Output format of the query.").Short('o').Default("promql").Enum("promql", "json")
+
 	queryInstantCmd := queryCmd.Command("instant", "Run instant query.")
-	queryServer := queryInstantCmd.Arg("server", "Prometheus server to query.").Required().String()
-	queryExpr := queryInstantCmd.Arg("expr", "PromQL query expression.").Required().String()
+	queryInstantServer := queryInstantCmd.Arg("server", "Prometheus server to query.").Required().String()
+	queryInstantExpr := queryInstantCmd.Arg("expr", "PromQL query expression.").Required().String()
+	queryInstantTime := queryInstantCmd.Flag("time", "Query evaluation time (RFC3339 or Unix timestamp).").String()
 
 	queryRangeCmd := queryCmd.Command("range", "Run range query.")
 	queryRangeServer := queryRangeCmd.Arg("server", "Prometheus server to query.").Required().String()
@@ -153,7 +155,7 @@ func main() {
 		os.Exit(CheckMetrics())
 
 	case queryInstantCmd.FullCommand():
-		os.Exit(QueryInstant(*queryServer, *queryExpr, p))
+		os.Exit(QueryInstant(*queryInstantServer, *queryInstantExpr, *queryInstantTime, p))
 
 	case queryRangeCmd.FullCommand():
 		os.Exit(QueryRange(*queryRangeServer, *queryRangeHeaders, *queryRangeExpr, *queryRangeBegin, *queryRangeEnd, *queryRangeStep, p))
@@ -427,7 +429,7 @@ func CheckMetrics() int {
 }
 
 // QueryInstant performs an instant query against a Prometheus server.
-func QueryInstant(url, query string, p printer) int {
+func QueryInstant(url, query, evalTime string, p printer) int {
 	config := api.Config{
 		Address: url,
 	}
@@ -439,11 +441,20 @@ func QueryInstant(url, query string, p printer) int {
 		return 1
 	}
 
+	eTime := time.Now()
+	if evalTime != "" {
+		eTime, err = parseTime(evalTime)
+		if err != nil {
+			fmt.Fprintln(os.Stderr, "error parsing evaluation time:", err)
+			return 1
+		}
+	}
+
 	// Run query against client.
 	api := v1.NewAPI(c)
 
 	ctx, cancel := context.WithTimeout(context.Background(), 2*time.Minute)
-	val, _, err := api.Query(ctx, query, time.Now()) // Ignoring warnings for now.
+	val, _, err := api.Query(ctx, query, eTime) // Ignoring warnings for now.
 	cancel()
 	if err != nil {
 		fmt.Fprintln(os.Stderr, "query error:", err)
diff --git a/cmd/promtool/main_test.go b/cmd/promtool/main_test.go
index 1d28cf292..a40ff0a86 100644
--- a/cmd/promtool/main_test.go
+++ b/cmd/promtool/main_test.go
@@ -19,6 +19,8 @@ import (
 	"net/http/httptest"
 	"testing"
 	"time"
+
+	"github.com/prometheus/prometheus/util/testutil"
 )
 
 func TestQueryRange(t *testing.T) {
@@ -27,41 +29,31 @@ func TestQueryRange(t *testing.T) {
 
 	p := &promqlPrinter{}
 	exitCode := QueryRange(s.URL, map[string]string{}, "up", "0", "300", 0, p)
-	expectedPath := "/api/v1/query_range"
-	gotPath := getRequest().URL.Path
-	if gotPath != expectedPath {
-		t.Errorf("unexpected URL path %s (wanted %s)", gotPath, expectedPath)
-	}
+	testutil.Equals(t, "/api/v1/query_range", getRequest().URL.Path)
 	form := getRequest().Form
-	actual := form.Get("query")
-	if actual != "up" {
-		t.Errorf("unexpected value %s for query", actual)
-	}
-	actual = form.Get("step")
-	if actual != "1" {
-		t.Errorf("unexpected value %s for step", actual)
-	}
-	if exitCode > 0 {
-		t.Error()
-	}
+	testutil.Equals(t, "up", form.Get("query"))
+	testutil.Equals(t, "1", form.Get("step"))
+	testutil.Equals(t, 0, exitCode)
 
 	exitCode = QueryRange(s.URL, map[string]string{}, "up", "0", "300", 10*time.Millisecond, p)
-	gotPath = getRequest().URL.Path
-	if gotPath != expectedPath {
-		t.Errorf("unexpected URL path %s (wanted %s)", gotPath, expectedPath)
-	}
+	testutil.Equals(t, "/api/v1/query_range", getRequest().URL.Path)
 	form = getRequest().Form
-	actual = form.Get("query")
-	if actual != "up" {
-		t.Errorf("unexpected value %s for query", actual)
-	}
-	actual = form.Get("step")
-	if actual != "0.01" {
-		t.Errorf("unexpected value %s for step", actual)
-	}
-	if exitCode > 0 {
-		t.Error()
-	}
+	testutil.Equals(t, "up", form.Get("query"))
+	testutil.Equals(t, "0.01", form.Get("step"))
+	testutil.Equals(t, 0, exitCode)
+}
+
+func TestQueryInstant(t *testing.T) {
+	s, getRequest := mockServer(200, `{"status": "success", "data": {"resultType": "vector", "result": []}}`)
+	defer s.Close()
+
+	p := &promqlPrinter{}
+	exitCode := QueryInstant(s.URL, "up", "300", p)
+	testutil.Equals(t, "/api/v1/query", getRequest().URL.Path)
+	form := getRequest().Form
+	testutil.Equals(t, "up", form.Get("query"))
+	testutil.Equals(t, "300", form.Get("time"))
+	testutil.Equals(t, 0, exitCode)
 }
 
 func mockServer(code int, body string) (*httptest.Server, func() *http.Request) {